Imagine you want to contribute to the org.eclipse.ui.perspectiveExtensions extension point, in order to plug your own views on a given, existing perspective.

Your perspective extension is going to be relative to… a perspective, right?
This perspective is identified by an ID, right?
But what is the actual ID of the perspective you want to extend? And what happens when, even knowing the exact ID of the perspective, you make a spelling mistake? Let me guess… You lose at least one hour of work in the so-called “id hell” 😉

That’s exactly why the PDE Manifest builder (i.e. the compiler of your plugin.xml against extension points schema and workspace/target platform plugins) will now handle a new kind of extension attribute : the ID!

When you want to add an “idref” attribute into an extension point, you just have to declare the attribute as “identifier”, and you then tell which identifier you want to refer to. And voilà !

The patch has not been committed on HEAD yet, but you can find the patch in the attachments of bug #181515.